<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>Animation of left property</title>
    <style>
         div {
             position: relative;
             left: 100px;
             height: 200px;
             width: 200px;
             background-color: #9bb;
             animation-name: bounce;
             animation-duration: 2s;
             animation-iteration-count: infinite;
             animation-direction: alternate;
             animation-timing-function: ease-in-out;
         }
         
         @keyframes bounce {
           from {
             left: 100px;
           }
           to {
             left: 300px;
           }
         }
         
     </style>
</head>
<body>
  <h1>Animation of 'left' property</h1>

  <p>The element below should bounce 200 pixels left and right continuously</p>
  
  <div id="target">
    This element should animate.
  </div>

</body>
</html>